Re: [quicwg/base-drafts] Does it make sense to try 0-RTT after Retry? (#2842)

Marten Seemann <> Tue, 25 June 2019 07:36 UTC

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From: Marten Seemann <>
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Subject: Re: [quicwg/base-drafts] Does it make sense to try 0-RTT after Retry? (#2842)
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Ok, I see that there's value in doing 0-RTT after a Retry, and furthermore, there seem to be good reasons (prevention of tampering by middle boxes) to disallow 0-RTT after a HelloRetryRequest in TLS 1.3, as @kazuho pointed out OOB.

Since we can assume that most (all?) server implementation will drop 0-RTT packets when sending a Retry, the only reasonable thing to do for a client is to treat all 0-RTT packets as lost and retransmit them. Considering that, it would make sense to require servers to drop all Retry packets from the first flight, as @kazuho suggests.

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